1. Field of the Invention
This invention is related in general to the field of information handling systems. In particular, the invention consists of a method of transmitting status information from a multitude of electronic devices over a common connector.
2. Description of the Prior Art
Electronic systems, such as printed circuit boards with numerous electronic components, can generate trace information that may be transmitted to other circuit boards, other electronic systems, other locations, or even a central monitoring station. This trace information may include an indication of the condition of the electronic components, their arrangement within the electronic system, their current activity, the contents of memory registers within the electronic components, or whether electric faults such as open or shorted circuits exists.
One example of this type of system is a printed circuit board containing multiple electronic components that include programmable input/output pins. Using a technique known as boundary scan, instructions may be loaded into the programmable components that instruct the programmable pins to transmit logic high, logic low, and high impedance signals. Other programmable pins may be instructed to simultaneously accept these transmitted signals as inputs. The result of this transmission and concurrent reception may be passed to an external connector on the printed circuit board. This external connector may be monitored to determine the status of the programmable electronic components or the connections between them.
Tracing of electronic equipment becomes more difficult as electronic system bus widths and clock speeds increase, and as the number of electric traces and number of component conditions increase. The major bottleneck for obtaining more information is the amount of information that may be transmitted through the external connector. Due to the limited bandwidth of a traditional connector, tracing is generally limited to a subset of the information of interest. This results in potentially useful information being inaccessible. Accordingly, it would be advantageous to increase the amount of trace information that may be transmitted through a connector.